Expose prometheus state to monitor dashboard

Add tests for presence and absence of cluster and deployment platform

app/helpers/environments_helper.rb

@@ -34,6 +34,7 @@ module EnvironmentsHelper
       "project-path" => project_path(project),
       "tags-path" => project_tags_path(project),
       "has-metrics" => "#{environment.has_metrics?}",
+      "prometheus-status" => "#{environment.prometheus_status}",
       "external-dashboard-url" => project.metrics_setting_external_dashboard_url
     }
   end

app/models/environment.rb

@@ -188,6 +188,10 @@ class Environment < ApplicationRecord
     prometheus_adapter.query(:environment, self) if has_metrics?
   end
 
+  def prometheus_status
+    deployment_platform&.cluster&.application_prometheus&.status_name
+  end
+
   def additional_metrics(*args)
     return unless has_metrics?
 

changelogs/unreleased/show-prometheus-is-updating.yml

+---
+title: Expose prometheus status to monitor dashboard
+merge_request: 18289
+author:
+type: fixed

spec/helpers/environments_helper_spec.rb

@@ -32,6 +32,7 @@ describe EnvironmentsHelper do
         'project-path' => project_path(project),
         'tags-path' => project_tags_path(project),
         'has-metrics' => "#{environment.has_metrics?}",
+        'prometheus-status' => "#{environment.prometheus_status}",
         'external-dashboard-url' => nil
       )
     end

spec/models/environment_spec.rb

@@ -727,6 +727,51 @@ describe Environment, :use_clean_rails_memory_store_caching do
     end
   end
 
+  describe '#prometheus_status' do
+    context 'when a cluster is present' do
+      context 'when a deployment platform is present' do
+        let(:cluster) { create(:cluster, :provided_by_user, :project) }
+        let(:environment) { create(:environment, project: cluster.project) }
+
+        subject { environment.prometheus_status }
+
+        context 'when the prometheus application status is :updating' do
+          let!(:prometheus) { create(:clusters_applications_prometheus, :updating, cluster: cluster) }
+
+          it { is_expected.to eq(:updating) }
+        end
+
+        context 'when the prometheus application state is :updated' do
+          let!(:prometheus) { create(:clusters_applications_prometheus, :updated, cluster: cluster) }
+
+          it { is_expected.to eq(:updated) }
+        end
+
+        context 'when the prometheus application is not installed' do
+          it { is_expected.to be_nil }
+        end
+      end
+
+      context 'when a deployment platform is not present' do
+        let(:cluster) { create(:cluster, :project) }
+        let(:environment) { create(:environment, project: cluster.project) }
+
+        subject { environment.prometheus_status }
+
+        it { is_expected.to be_nil }
+      end
+    end
+
+    context 'when a cluster is not present' do
+      let(:project) { create(:project, :stubbed_repository) }
+      let(:environment) { create(:environment, project: project) }
+
+      subject { environment.prometheus_status }
+
+      it { is_expected.to be_nil }
+    end
+  end
+
   describe '#additional_metrics' do
     let(:project) { create(:prometheus_project) }
     let(:metric_params) { [] }